1. Field of the Invention
The present invention relates to a BaO-xTiO.sub.2 dielectric ceramic composition, and more particularly, to a BaO-xTiO.sub.2 dielectric ceramic composition having a Ba.sub.2 Ti.sub.9 O.sub.20 /(BaTi.sub.4 O.sub.9 +Ba.sub.2 Ti.sub.9 O.sub.20) ratio of less than 0.19 for preventing the occurrence of hexagonal pattern cracks.
The present invention is applicable for impedance matching or the like in a dielectric resonator (particularly, one with a large size of 50 mm.phi. or more), a microwave integrated circuit board or impedance matching in various microwave circuits in a microwave region.
2. The Related Art of the Invention
There have been known various BaO-xTiO.sub.2 dielectric ceramic compositions, for example, disclosed in Japanese Patent Publication No. hei 1-37807, Japanese Patent Laid-open No. sho 61-10806, Japanese Patent Laid-open No. sho 61-10807, Japanese Patent Laid-open No. sho 63-117957 and the like.
However, the conventional dielectric ceramic compositions described above have a disadvantage of causing hexagonal pattern cracks on the surface of the resonator in a baking process thereby significantly reducing the yield. In particular, the large size resonator has such a tendency to cause the above cracks.